UPDATE - just got a notification that I had a successful backup - second 
in 5 days.  This time it created another Manifest file and two folders - 
a difftar.gz and an sigtar.gz.  Happy with that but it is weird that I 
got the errors creating directories first.  I will see what happened 
next Thursday when it is next scheduled.  I thought I got an error from 
the automatic backup and then again when I tried it manually so I don't 
know why it tried again but I am happy with the outcome.  It does seem 
to be a bug.

John

On 3/28/19 9:54 AM, John Bell wrote:
> Michael,
>
> Thanks for still helping me with this.
>
> Just to update you on where I am:  As it had been a month without a 
> backup, I gave in and bought another 1TB internal SATA drive and 
> formatted it as Ext4.  The first backup on this drive created a bunch 
> of files but then stopped with a Backup Failed message.  I checked for 
> advice on the internet and someone had been successful by formatting 
> the disk as NTFS, so I deleted the whole new drive and reformatted - a 
> long process.
>
> I then ran a backup with no encryption password and it succeeded, 
> creating a full backup.
>
> Today Deja Dup attempted a backup on its original Thursday schedule 
> (last backup was 5 days ago and the schedule is weekly so it must be 
> back to its original setup)  and failed leaving me with the following 
> message:
>
>     Error creating directory /media/john/20190323 Backups: Permission 
> denied
>
> I have just followed your instruction to delete the backup encryption 
> password and it has just given me the same error message, not 
> prompting me for a password.  I will reboot and try again.  If that 
> doesn't work I will have to delete my last backup to create enough 
> room on the disk (full backup is a little under 600GB so only 400GB 
> left) for another full backup, which leaves me a little vulnerable, 
> and give a new folder name.
>
> Rebooting was no help.
>
> Why is it trying to create 'directory /media/john/20190323 Backups', 
> have I specified the location incorrectly?  The new drive is called 
> '20290323 Backups' and the last full backup created no separate folder 
> in that drive.  The first entry in that disk is 
> 'duplicity-full.20190323T183857Z.manifest' and the rest of the entries 
> are separate folders called xxxx.volNNN.difftar.gz each 52.4 MB.
>
> I also get frequent, almost daily, Ubuntu crash reports which I seldom 
> got under Ubuntu 16.04.  I attach screenshots covering the whole 
> content of the error with all the topics compressed, but I do have 
> separate screenshots with full details if you think any would help.  
> Zeitgeist was the prime cause of the problem on this occasion.
>
> Thank you very much for your help.
>
> John Bell
>
> On 3/23/19 3:16 PM, Michael Terry wrote:
>> Hello, sorry for slow response.
>>
>> Selecting 'local folder' should be fine. That seems appropriate for your
>> case.
>>
>> The permission error you're getting is odd. Is the drive sometimes
>> mounted differently?
>>
>> To clear out any saved password, open the "Passwords and Keys" app and
>> look for the saved "Backup encryption password". Delete that and re-run
>> your backup. It should prompt for the password.
>>
>> If for some reason, that still doesn't work, the worst case scenario is
>> to back up to a new folder. This will create a new backup series and you
>> can set a new password.
>>
>> (I'm sorry you're having these problems! Let me know if any of these
>> attempts help.)
>>